article
Synthesis, structural characterization and magnetic properties of the monoclinic ordered double perovskites BaLaMSbO6, with M = Mn, Co and Ni
Fecha
2014Autor
Blanco, M. Cecilia
De Paoli, Juan M.
Ceppi, Sergio
Tirao, Germán Alfredo
Nassif, Vivian M.
Guimpel, J.
Carbonio, Raúl E.
Institución
Resumen
Double perovskites BaLaMnSbO6, BaLaCoSbO6 and BaLaNiSbO6, were synthesized by conventional ceramic method in air, as polycrystalline powders. The Mn and Ni compounds belong to the I 2/m monoclinic space group, while the Co perovskite belongs to the I 4/m tetragonal space group. Effective presence of Mn2+ has been well established by X-ray emission spectroscopy for BaLaMnSbO6, and there is no evidence of Mn3+. BaLaCoSbO6 and BaLaNiSbO6 only show the expected 3D-antiferromagnetic behavior typical of super-superexchange interactions, while BaLaMnSbO6 displays signs of superparamagnetism in the 40–160 K range, which arises from unbalanced antiferromagnetism inside nanoclusters formed by regions which are rich in Mn2+–O2−–Mn2+ paths. Neutron powder diffraction data for BaLaMnSbO6 reveals that at 3 K, only long range order antiferromagnetic arrangement of Mn2+ spins on 2d octahedral sites is obtained.